Surge current refers to an electrical current that occurs for a short period of time and is much higher than the normal operating current. This phenomenon can be caused by many different factors, such as lightning strikes, power outages and even the switching on and off of large electric motors. Some synonyms for surge current include peak current, transient current, impulse current, and spike current. These terms are often used interchangeably to describe the same electrical phenomenon. A surge protector is commonly used to protect electrical devices from this type of current, which can cause damage or even complete failure of sensitive electronic equipment.